Older individuals with ASD show deficits in the pragmatic and spontaneous use of emotional information, but little is known about emotional processing in the early stages of ASD. Our preliminary work suggests that deficits in emotion processing are present as early as at 12 months in the affected infants. In typical development, infants detect and orient towards affective cues in the first months of life. These attentional biases for affectively valenced information play a critical role in the development of attachment, communication, empathy, and non-social cognition. Considering that later-emerging and more complex emotion processing and regulation skills are affected in toddlers with ASD, this project examines early- emerging emotional attention skills such as capture by, hold by, and preference for affective cues. Key questions are: Are deficits in emotional attention general, affecting multiple modalities (e.g. faces, biomotion, and prosodic cues) and attentional mechanisms (e.g., capture, bias, and preference)? Is orienting to specific emotions preserved (e.g. fear, anger, and joy)? Is there an association between the child's attentional biases for perceiving the emotional cues of others and their own emotional functioning? What is the relationship between early emotional dysfunction and later core and comorbid symptoms? We propose to examine these questions in 12-24-month-old toddlers with ASD, developmental delay (DD) and typical development (TD) (T1) followed prospectively at 36-42 months (T2). At T1 we will evaluate aspects of emotional attention in response to facial expressions, body movements, and prosodic cues using eye-tracking. We will also examine in vivo aspects of emotional functioning and regulation skills. Combining eye-tracking and behavioral tasks will allow us to both quantify emotional functioning at the early stage of syndrome emergence in an unprecedented fashion and to evaluate their unique contribution to outcomes 1-2 years later. This project will allow us to identify preserved domains of affective processing (upon which therapies can be scaffolded), identify deficient domains (which may be targeted directly for treatment), advance our understanding of the unique contribution of emotional disturbance to core and comorbid symptoms of ASD (helping to identify novel predictors of outcome and homogenous subgroups within ASD), and suggest mechanisms that may illuminate the role of emotional attention difficulties in the etiology of autism.